Sensory Panel Set Up

Author: Anne Hood | Major: Food Science | Semester: Fall 2024

Hi, my name is Anne Hood, and I am a senior food science major in the Bumpers College of Agricultural, Food, and Life Sciences. This past semester, I worked in Dr. Scott Lafontaine’s brewing lab to determine the flavor thresholds of iron sulfate and iron (III) chloride in nonalcoholic beer. A threshold is defined as the point at which a person begins to notice a stimulus, providing a useful measure of sensitivity to a tastant. My research involved conducting a sensory panel with 27 participants to identify these thresholds.

The hope for my study is to provide beer producers with critical information about the point at which iron becomes detectable in a beer-like matrix such as nonalcoholic beer. Since iron is an undesirable flavor in beer and other beverages, establishing definitive thresholds will help producers minimize off-flavors and optimize product quality. This research is especially significant because there is currently no data on flavor thresholds of iron in beer, making this a novel area of study. Moreover, the methodology and findings could be expanded to study thresholds for other transition metals beyond iron, broadening the real-world applications for brewing and beverage industries.

Participants completed seven triangle tests; a sensory method used to detect differences between samples. Each test consisted of three samples—two identical and one different—with the spiked sample increasing in concentration across the seven triangles to minimize sensory fatigue. The threshold was determined as the concentration level at which participants correctly identified the spiked sample but struggled with further identification due to sensory overload or inaccuracies. Next semester, I plan to refine this project, including testing panelists whose thresholds were not determined in the initial trials. Currently, the data collected is being processed and analyzed, and the final results will be presented during my thesis defense in the spring of 2025.

I met Dr. Lafontaine during my sophomore year in his brewing science course, which sparked my interest in brewing research. When considering topics for my honors thesis, I reached out to him, and he proposed several potential projects. I selected this particular project because of its combination of sensory science and brewing applications, aligning well with my interests.

This project taught me the intricacies of sensory science and the challenges of designing and conducting experiments. On a personal level, I gained skills in planning, problem-solving, and adapting to unexpected outcomes.

One of the biggest challenges was recruiting participants for the sensory panel. While our goal was to include 50 panelists, we ultimately had 27—still a solid number, though less than anticipated. Organizing the panel sessions was also time-consuming, as each participant needed a unique combination of three-digit cup codes that corresponded correctly to the Qualtrics survey. All together over 1000 cups needed to be labeled. Additionally, calculating and verifying the dilution schemes required careful attention to detail to ensure that the spiked sample was detectable midway through the triangle test series. By testing and refining the dilution schemes multiple times, we ensured the process was reliable before bringing in participants.

Dr. Lafontaine played a role in guiding my research. He assisted with ordering supplies, structuring the sensory portion of the study, and verifying concentration ranges for the dilution scheme. Graduate and PhD students Bernardo Pontes Guimaraes, Andrew Maust, and Matthew Aitkens also provided invaluable support. They helped prepare over 200 bottles of nonalcoholic beer for the control and spiked samples and assisted in running the sensory room during panel sessions. Bernardo, in particular, managed the sensory room logistics, ensuring smooth transitions between sessions.

Next semester, I aim to further refine my research by expanding the sensory panel and addressing gaps in the current data. Beyond my thesis, I plan to pursue dental school, where I hope to integrate my passion for science into a fulfilling career.